1. Field of the Invention
This invention relates to windrowers for grown product and, more particularly, to a windrower having a cross conveyor for selectively discharging grown product at different lateral locations.
2. Background Art
Windrowers are used to dig grown product, such as potatoes, out of the ground and discharge an accumulation of the potatoes from multiple rows at one lateral location. Thereafter, the accumulated potatoes may be further windrowed or picked up by a harvester. Windrowing is carried out primarily to reduce the number of passes required by a harvester, that is more expensive, and requires more skill, to operate than a windrower.
Potatoes are normally planted in parallel rows spaced apart at uniform distances of 32-38 inches. Commonly a windrower will continuously simultaneously dig 2, 4 or 6 rows of potatoes as the windrower is advanced parallel to the rows.
Windrowers are generally constructed with components referred to as primary, secondary, and rear cross conveyors. The primary conveyor has blades that dig the potatoes out of the rows. The potatoes and any gathered soil are conveyed upwardly and oppositely to the advancing direction for the windrower during which some of the soil breaks away from the potatoes and deposits on the underlying terrain. The potatoes drop as they transfer from the primary conveyor to the secondary conveyor. This action tends to break up adhered dirt clods. Additional dirt separates as the potatoes are advanced upwardly and oppositely to the advancing direction for the windrower by the secondary conveyor. A third conveyor operates outside of the secondary conveyor and strips vines from the potatoes and dirt. The potatoes drop once again to the cross conveyor, as an incident of which further dirt dislodges from the potatoes. The cross conveyor directs the potatoes laterally for accumulated discharge between two adjacent rows next to the windrower. Precise lateral placement of the discharging potatoes between adjacent rows may require a lateral adjusting capability, for reasons explained below.
When potatoes are planted, oftentimes wheel markers or GPS steering are used to control movement of the towing vehicle/tractor and thereby maintain precise alignment between successive passes so that the row spacing does not deviate throughout an entire planting area. If wheel markers or GPS steering are not available, or otherwise not used, the spacing between a row formed on a subsequent pass may not be consistently spaced in relationship to the adjacent, outer row from an earlier pass. The first row on a pass, that is adjacent to the outer row on a prior pass, is referred to in the industry as a “guess row”.
As the potatoes are discharged from the cross conveyor, they are commonly placed between the outer row of a prior pass and the guess row. If the guess row spacing deviates significantly and no adjustment to the lateral discharge location is effected, the potatoes may not be placed between rows where they would otherwise be picked up by a subsequent pass of a windrower or harvester.
It is generally not practical to compensate for this condition by steering the tractor to one side. That is because the tires on the tractor must ride in the region between rows. The tire width of such tractors is generally sufficiently large that only a slight lateral steering of the tractor is possible before the wheels travel partially or fully into the rows.
It is known to adjust the cross conveyor in a manner whereby the potatoes can be discharged into rows at different lateral locations, thereby permitting the tractor to travel in a straight line with the tires between adjacent rows. This adjustment is in one known form effected by changing the lateral inclination of the cross conveyor. As the angle of the cross conveyor increases to effectively elevate the discharge end, the discharge end shifts laterally inwardly relative to the tractor. While this alleviates the above problem to a certain extent, the resulting discharge of potatoes becomes less precise. That is, the potatoes discharge from a greater height and may bounce off of each other and the underlying terrain, as a result of which the potatoes may be deposited on a wider lateral strip. As a consequence, some of the discharged potatoes may not be picked up by a windrower or harvester in a following pass.
It is also known to construct cross conveyors in a manner that they can be manually released and re-mounted in a laterally shifted position to account for row spacing deviations. However, it is not common that row spacing deviation is consistent over a sufficient area to make this exercise practical. Given fluctuations in row spacing, were this adjustment technique practiced, it would be required that the operator repeatedly stop the tractor and make numerous adjustments to accommodate the field conditions. This would be a difficult and time consuming exercise, as a consequence of which most operators will take other steps to accommodate the deviations from the consistent row spacing. Most commonly, the attempted solution is to steer the tractor laterally as dictated by the particular spacing deviation. The ability to do so is limited and may lead to either ineffective compensation or the undesired drifting of the tractor wheels directly into the rows.
The industry has contended with the above problems since there has been lacking a cross conveyor construction that will allow straight travel by a tractor and can be adjusted as the tractor is advancing to compensate for deviating row spacing and cause precise discharge of potatoes between rows.